South Australian racing is bracing itself for the biggest race day crowd of the modern era when Australia's undefeated champion, Black Caviar shoots for her 20th consecutive victory at Morphettville on Saturday.

Black Caviar will contest the $400,000 Group 1 Sportingbet Classic (1200m) at the headquarters of racing in Adelaide and will only have nine rivals to overcome as she embarks on eclipsing the 19 win mark she shares with Desert Gold and Gloaming.

The champ will be trainer Peter Moody's sole representative in the race after he resisted the temptation to run any stable mates to meet Black Caviar in the feature sprint despite also nominating Curtana, Kulgrinda and Mid Summer Music.

Black Caviar has drawn beautifully in barrier three in the field of ten which includes fellow Caulfield-trained mares Lone Rock (Robert Smerdon) and Sistine Angel (Andrew Noblet) along with Mark Kavanagh's Valentine Miss and the Robbie Griffiths-trained Spurcific completing the Victorian contingent of challengers.

Local hopes include Just Sybil, trained by Brain Mueller from Strathalbyn and David Jolly's Shekinaar while two horses have made the trip across the Nullarbor with Stan Bates (All Fraired Up) and Aquanita Racing's Simon Miller (Power Princess) both travelling from Western Australia.

Of Black Caviar's nine opponents on Saturday, only Lone Rock has competed in a race against the champion mare, finishing 4 ½ lengths from her in 5th place in the Coolmore Lightning Stakes (1000m) at Flemington on 18 February.

The Sportingbet Classic is race 7 on the program at 3.53pm (SA time).

The second feature Group 1 event at Morphettville on Saturday is the $400,000 Schweppes Oaks (2000m) for three-year-old fillies where a full field has been assembled.

Bart Cummings, who last won the race in 1994 with Tristalove, has accepted with Kewney Stakes winner Empress Rock.

Empress Rock has drawn barrier nine in the field of 16 (plus four emergencies) and will again be ridden by regular rider, Steven Arnold.

Among the other key runners in the 31st running of the Oaks are the Leon Corstens-trained Rahveel (barrier 15) and the three Mathew Ellerton & Simon Zahra-trained fillies Secret Liaison (11), Sharnee Rose (7) and Spelldancer (19).

Anthony Freedman, currently 3rd in the Victorian metropolitan trainer's premiership, has last start winner Crucial engaged and has drawn barrier 10 with Vlad Duric aboard.

Freedman is aiming to add to the honour roll of Freedman trained winners of the Schweppes Oaks (registered as Australasian Oaks) with brother Lee winning the race on four occasions including his first ever group 1 success with Miss Clipper in 1984.